Linney, Thanks for those links. It seems the KISS principle is still alive & well.
I found the following worked fine -
Set the Day, Time & Program to run, but don't set any restrictions.
In Task, Properties, General Tab Select - "Run whether user is logged in or not"
- "Do not store password"
- "Run with highest privileges"
Triggers Tab Set Day & Time, but under "Advanced Settings" only Select "Enabled"
Conditions Tab Leave all blank
Settings Tab Select - "Allow task to run on demand"
Leave all others blank
Cheers Sue99